<div class="tn-tabs">
    <a class="tab {$pn=='course/index'?'active':''}" href="/course/{$course.id}/info">介绍</a>
    <a class="tab {$pn=='course/task'?'active':''}" href="/course/{$course.id}/task">目录</a>
    <a class="tab {$pn=='course/note'?'active':''}" href="/course/{$course.id}/note">笔记</a>
</div>